Signals

The water-in-a-pipe analogy is OK, but I prefer to think of it as a pipe full of marbles or bearing balls. You can also build a nice little demonstrator to show this. You push a marble in one end, and another "instantly" pops out of the other. The marbles all push on each other and the force propagates at the speed of sound (in marbles). The analogy with electrons would be the speed of light.

Now, about signal propagation: Just imagine you push a marble, wait a second, push another, wait 2 seconds or whatever... the marbles that came out the other end would be different marbles than the ones that went in, but they would move on the same schedule. And if all the marbles look identical, then you won't be able to tell that they weren't the same ones that went in... just like you can't tell with electrons.

Hope this helps.

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

Hi, I remembered I read from a book in which it roughly said "The drift rate of an electron is about 35cm/h (I can't confirm this figure now cos I did not know where the book I read was)" So if it is the case, how come the signal coming from the source instantly appeared on its output at a lightning speed... There was also a reference which said electric current is like a water pipeline, the electron just pushes the one on in front of it which creates an instantanous "Power transfer"? and I understand this. But what about signals? why the signal also has the same speed (due to electric field)? What is the significance of frequencies (Megahertz/Gigahertz, 3GHz CPU, 400MHz RAM etc) in such cases? There is more to ask for this question because I just made up my mind last night so I've forgotten... Thanks J

Take the internet as an example, If I put an 1 onto the network, how come the other one in the other side of world (the remote computer) knows I am speaking of an

"Jacky Luk" ¼¶¼g©ó¶l¥ó·s»D:4305a4a9$1@127.0.0.1...

So My question why the signal is passed on so fast!!!! That's what I can remember from yesterday....

"Jacky Luk" ¼¶¼g©ó¶l¥ó·s»D:4305a9a6$1@127.0.0.1...

OK, I think you said that you understand that the energy of an electric field moves a bit less than the speed of light, while the actual electron drift is significantly slower.

The significance of signal frequency is bandwidth and processing speed. You appear to be asking about the speed of CPU and memory in a computer, so the answer is rather simple there. The 3GHz CPU you speak of has a clock rate of 3GHz, meaning it can process one simple instruction in 1/3,000,000,000 second, or one every 0.333 nanoseconds. This in comparison to the ancient 100MHz Pentium I, which processed one simple instruction every ten nanoseconds. Memory access speed is a similar calculation, with some caveats depending on type of memory.

Bandwidth of transmitted information is another subject entirely.